The present invention relates to a circuit arrangement for the formation of group signals following each other in time for use in direction finding systems, particularly involving sound wave propagation in water.
Circuit arrangements of the type under consideration, one example of which is disclosed in U.S. Pat. No. 3,810,082, can include a receiving system having a circular array of receiving transducers. A selected group of the transducers, which is located on the arc of the circle defining the locus of the array, is used for forming a group characteristic.
The received signals of the transducers of one group each are delayed for the formation of a group signal as though the transducers were not arranged on the arc but on the corresponding chord. This chord is located normally to the direction of the group characteristic associated with this transducer group. The received signals of these transducers of a group, which are correctly delayed in time, form, when summed up, the group signal belonging to this group characteristic.
In accordance with the above-cited patent, all transducers of the receiving system are interrogated for this compensation in an adjacent sequence in a repeated manner with clock pulses and their momentary signals received are read into a memory at the same rate through a read-in point and they are shifted in the memory in the course of the interrogation continuously further away from the read-in point. Selected memory locations are read-out to an adder whose output presents group signals which appear successively in the same rhythm as the interrogation whereby a direction, or an angle, is to be assigned to each group signal.
Different circuit arrangements are known for the evaluation of such group signals in the technology for sound wave propagation in water for the purpose of processing, particularly for the removal of noise, which use multiplicative methods.